The Massive M31 Cluster G1: Detailed Chemical Abundances from Integrated Light Spectroscopy

Abstract

G1, also known as Mayall II, is one of the most massive star clusters in M31. Its mass, ellipticity, and location in the outer halo make it a compelling candidate for a former nuclear star cluster. This paper presents an integrated light abundance analysis of G1, based on a moderately high-resolution (R=15,000) spectrum obtained with the High Resolution Spectrograph on the Hobby-Eberly Telescope in 2007 and 2008. To independently determine the metallicity, a moderate resolution (R~4,000) spectrum of the calcium-II triplet lines in the near-infrared was also obtained with the Astrophysical Research Consortium's 3.5-m telescope at Apache Point Observatory. From the high-resolution spectrum, G1 is found to be a moderately metal-poor cluster, with [Fe/H]=-0.98+/-0.05. G1 also shows signs of alpha-enhancement (based on Mg, Ca, and Ti) and lacks the s-process enhancements seen in dwarf galaxies (based on comparisons of Y, Ba, and Eu), indicating that it originated in a fairly massive galaxy. Intriguingly, G1 also exhibits signs of Na and Al enhancement, a unique signature of GCs -- this suggests that G1's formation is intimately connected with GC formation. G1's high [Na/Fe] also extends previous trends with cluster velocity dispersion to an even higher mass regime, implying that higher mass clusters are more able to retain Na-enhanced ejecta. The effects of intracluster abundance spreads are discussed in a subsequent paper. Ultimately, G1's chemical properties are found to resemble other M31 GCs, though it also shares some similarities with extragalactic nuclear star clusters.

arXiv commentAccepted for publication in MNRAS

References in corpus (107)

• The chemical composition of the Sun
• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• The Initial Mass Function of Stars: Evidence for Uniformity in Variable Systems
• A large stellar evolution database for population synthesis studies. I. Scaled solar models and isochrones
• Low Temperature Opacities
• The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
• Star Formation Histories, Abundances and Kinematics of Dwarf Galaxies in the Local Group
• Elemental Abundance Survey of The Galactic Thick Disk
• Extragalactic Globular Clusters and Galaxy Formation
• Stellar Chemical Signatures And Hierarchical Galaxy Formation
• Multiple Stellar Populations in Globular Clusters
• A large stellar evolution database for population synthesis studies. II. Stellar models and isochrones for an alpha-enhanced metal distribution
• Na-O Anticorrelation and HB. VIII. Proton-capture elements and metallicities in 17 globular clusters from UVES spectra
• Neutron-Capture Elements in the Early Galaxy: Insights from a Large Sample of Metal-Poor Giants
• Properties of stellar generations in Globular Clusters and relations with global parameters
• VLT/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies: I. Nucleosynthesis and Abundance Ratios
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. IX. The Atlas of Multiple Stellar Populations
• Origin of the system of globular clusters in the Milky Way
• Evidence for Stellar Substructure in the Halo and Outer Disk of M31
• Tracing Galaxy Formation with Stellar Halos II: Relating Substructure in Phase- and Abundance-Space to Accretion Histories
• Non-LTE calculations for neutral Na in late-type stars using improved atomic data
• Nuclear Star Clusters
• Sagittarius: The Nearest Dwarf Galaxy
• NLTE line formation of Fe in late-type stars II: 1D spectroscopic stellar parameters
• Chemical Abundances for 855 Giants in the Globular Cluster Omega Centauri (NGC 5139)
• A Catalog of Globular Cluster Systems: What Determines the Size of a Galaxy's Globular Cluster Population?
• The large-scale structure of the halo of the Andromeda Galaxy Part I: global stellar density, morphology and metallicity properties
• An Intermediate-Mass Black Hole in the Globular Cluster G1: Improved Significance from New Keck and Hubble Space Telescope Observations
• A high resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy
• A HST Census of Nuclear Star Clusters in Late-Type Spiral Galaxies: II. Cluster Sizes and Structural Parameter Correlations
• A 20 Thousand Solar Mass Black Hole in the Stellar Cluster G1
• The supernova delay time distribution in galaxy clusters and implications for Type-Ia progenitors and metal enrichment
• Mayall II = G1 in M31: Giant Globular Cluster or Core of a Dwarf Elliptical Galaxy ?
• Non-LTE line formation of Fe in late-type stars - III. 3D non-LTE analysis of metal-poor stars
• Chemistry of the Sagittarius Dwarf Galaxy: a Top-Light IMF, Outflows and the R-Process
• The large-scale structure of the halo of the Andromeda galaxy II. Hierarchical structure in the Pan-Andromeda Archaeological Survey
• Evidence for an accretion origin for the outer halo globular cluster system of M31
• A Dynamical Model for the Globular Cluster G1
• Iron and s-elements abundance variations in NGC5286: comparison with anomalous globular clusters and Milky Way satellites
• Homogeneous Analysis of Globular Clusters from the APOGEE Survey with the BACCHUS Code. II. The Southern Clusters and Overview
• Star Clusters in M31: II. Old Cluster Metallicities and Ages from Hectospec Data
• Ten Year Review of Queue Scheduling of the Hobby-Eberly Telescope
• Sodium-oxygen anticorrelation and neutron capture elements in Omega Centauri stellar populations
• The R-Process Alliance: First Release from the Northern Search for r-Process Enhanced Metal-Poor Stars in the Galactic Halo
• The chemical composition of red giant stars in four intermediate-age clusters of the Large Magellanic Cloud
• The Next Generation Virgo Cluster Survey. XXIII. Fundamentals of nuclear star clusters over seven decades in galaxy mass
• Iron and neutron-capture element abundance variations in the globular cluster M2 (NGC 7089)
• The SLUGGS Survey: Calcium Triplet-based Spectroscopic Metallicities for Over 900 Globular Clusters
• Chemical Compositions of Red Giant Stars in Old Large Magellanic Cloud Globular Clusters
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XIX. A Chemical Tagging of the Multiple Stellar Populations Over the Chromosome Maps
• Globular cluster systems in nearby dwarf galaxies - II. Nuclear star clusters and their relation to massive Galactic globular clusters
• The last breath of the Sagittarius dSph
• Stellar populations and star formation histories of the nuclear star clusters in six nearby galaxies
• The outer halo globular cluster system of M31 - II. Kinematics
• A new abundance scale for the globular cluster 47 Tuc
• The Stellar Populations of M31 Halo Substructure
• The Nature and Origin of Substructure in the Outskirts of M31. I. Surveying the Stellar Content with HST/ACS
• Globular Cluster Abundances from High-Resolution Integrated Light Spectra, I: 47 Tuc
• The metallicity spread and the age-metallicity relation of Omega Centauri
• M31 Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy
• Global Properties of `Ordinary' Early-type Galaxies: photometry and spectroscopy of stars and globular clusters in NGC 4494
• Chemical abundances in the nucleus of the Sagittarius dwarf spheroidal galaxy
• Primordial r-process Dispersion in Metal-Poor Globular Clusters
• Nuclear Star Clusters and the Stellar Spheroids of their Host Galaxies
• The absence of radio emission from the globular cluster G1
• An updated survey of globular clusters in M 31. III. A spectroscopic metallicity scale for the Revised Bologna Catalog
• Star Clusters in M31. V. Evidence for Self-Enrichment in Old M31 Clusters from Integrated Spectroscopy
• Mass-to-Light Ratios for M31 Globular Clusters: Age-Dating and a Surprising Metallicity Trend
• The Next Generation Fornax Survey (NGFS): IV. Mass and Age Bimodality of Nuclear Clusters in the Fornax Core Region
• Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy. IV. The Large Magellanic Cloud: $\alpha$, Fe-peak, Light, and Heavy Elements
• Chemical composition of the old globular clusters NGC 1786, NGC 2210 and NGC 2257 in the Large Magellanic Cloud
• Virgo Redux: The Masses and Stellar Content of Nuclei in Early-Type Galaxies from Multi-Band Photometry and Spectroscopy
• The Detailed Chemical Properties of M31 Star Clusters I. Fe, Alpha and Light Elements
• Evidence for multiple populations in the intermediate age cluster Lindsay 1 in the SMC
• The chemical composition of red giants in 47 Tucanae I: Fundamental parameters and chemical abundance patterns
• Metal-poor nuclear star clusters in two dwarf galaxies near Centaurus A suggesting formation from the in-spiraling of globular clusters
• The outer halo globular cluster system of M31 - III. Relationship to the stellar halo
• No evidence for internal rotation in the remnant core of the Sagittarius dwarf
• A Chemical Composition Survey of the Iron-Complex Globular Cluster NGC 6273 (M 19)
• Integrated Light Chemical Tagging Analyses of Seven M31 Outer Halo Globular Clusters from the Pan-Andromeda Archaeological Survey
• Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy. III. The Large Magellanic Cloud: Fe and Ages
• Keck Spectroscopy of Red Giant Stars in the Vicinity of M31's Massive Globular Cluster G1
• Spectrum Syntheses of High Resolution Integrated Light Spectra of Galactic Globular Clusters
• Infrared High-Resolution Integrated Light Spectral Analyses of M31 Globular Clusters from APOGEE
• Detailed abundance analysis of globular clusters in the Local Group: NGC 147, NGC 6822, and Messier 33
• Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy. II. Expanding the Metallicity Range for Old Clusters and Updated Analysis Techniques
• Deriving Metallicities From the Integrated Spectra of Extragalactic Globular Clusters Using the Near-Infrared Calcium Triplet
• Chemical enrichment mechanisms in Omega Centauri: clues from neutron-capture elements
• The Next Generation Fornax Survey (NGFS): VII. A MUSE view of the nuclear star clusters in Fornax dwarf galaxies
• Structural Parameters of Mayall II = G1 in M31
• Spectroscopic detection of multiple populations in the ~2 Gyr old cluster Hodge 6 in the LMC
• Formation of giant globular cluster G1 and the origin of the M31 stellar halo
• Detailed abundances from integrated-light spectroscopy: Milky Way globular clusters
• Detailed Chemical Abundances of Four Stars in the Unusual Globular Cluster, Palomar 1
• The WAGGS project - II. The reliability of the calcium triplet as a metallicity indicator in integrated stellar light
• The horizontal branch luminosity vs metallicity in M31 globular clusters
• Probing the Nature of the G1 Clump Stellar Overdensity in the Outskirts of M31
• Hubble Space Telescope analysis of stellar populations within the globular cluster G1 (Mayall II) in M31
• Evidence for metallicity spreads in three massive M31 globular clusters
• Optimal Integrated Abundances for Chemical Tagging of Extragalactic Globular Clusters
• The Not So Extraordinary Globular Cluster M31 037 - B327
• The chemical composition of red giants in 47 Tucanae. II. Magnesium isotopes and pollution scenarios
• The horizontal branch morphology of M31 globular clusters. Extreme second parameter effect in outer halo clusters
• The Integrated Calcium II Triplet as a Metallicity Indicator: Comparisons with High Resolution [Fe/H] in M31 Globular Clusters
• Chemical Abundances of Two Stars in the Large Magellanic Cloud Globular Cluster NGC~1718
• Modelling of integrated-light spectra from the optical to the near-infrared: the globular cluster G280 in M31
• A quick guide to FXCOR

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• On the Use of Field RR Lyrae as Galactic Probes -- VIII. Early Formation of the Galactic Spheroid
• Synthetic stellar spectra to study multiple populations in globular clusters: an extended grid and the effects on the integrated light